// SPDX-License-Identifier: GPL-2.0-or-later

  /* SCTP kernel implementation

   * (C) Copyright IBM Corp. 2001, 2003
   * Copyright (c) Cisco 1999,2000
   * Copyright (c) Motorola 1999,2000,2001
   * Copyright (c) La Monte H.P. Yarroll 2001
   *

   * This file is part of the SCTP kernel implementation.

   *
   * A collection class to handle the storage of transport addresses.
   *

   * Please send any bug reports or fixes you make to the
   * email address(es):

   *    lksctp developers <linux-sctp@vger.kernel.org>

   *

   * Written or modified by:
   *    La Monte H.P. Yarroll <piggy@acm.org>
   *    Karl Knutson          <karl@athena.chicago.il.us>
   *    Jon Grimm             <jgrimm@us.ibm.com>
   *    Daisy Chang           <daisyc@us.ibm.com>

   */
  
  #include <linux/types.h>

  #include <linux/slab.h>

  #include <linux/in.h>
  #include <net/sock.h>
  #include <net/ipv6.h>
  #include <net/if_inet6.h>
  #include <net/sctp/sctp.h>
  #include <net/sctp/sm.h>
  
  /* Forward declarations for internal helpers. */

  static int sctp_copy_one_addr(struct net *net, struct sctp_bind_addr *dest,
  			      union sctp_addr *addr, enum sctp_scope scope,
  			      gfp_t gfp, int flags);

  static void sctp_bind_addr_clean(struct sctp_bind_addr *);
  
  /* First Level Abstractions. */
  
  /* Copy 'src' to 'dest' taking 'scope' into account.  Omit addresses
   * in 'src' which have a broader scope than 'scope'.
   */

  int sctp_bind_addr_copy(struct net *net, struct sctp_bind_addr *dest,

  			const struct sctp_bind_addr *src,

  			enum sctp_scope scope, gfp_t gfp,

  			int flags)

  {
  	struct sctp_sockaddr_entry *addr;

  	int error = 0;
  
  	/* All addresses share the same port.  */
  	dest->port = src->port;
  
  	/* Extract the addresses which are relevant for this scope.  */

  	list_for_each_entry(addr, &src->address_list, list) {

  		error = sctp_copy_one_addr(net, dest, &addr->a, scope,

  					   gfp, flags);
  		if (error < 0)
  			goto out;
  	}
  
  	/* If there are no addresses matching the scope and
  	 * this is global scope, try to get a link scope address, with
  	 * the assumption that we must be sitting behind a NAT.
  	 */
  	if (list_empty(&dest->address_list) && (SCTP_SCOPE_GLOBAL == scope)) {

  		list_for_each_entry(addr, &src->address_list, list) {

  			error = sctp_copy_one_addr(net, dest, &addr->a,

  						   SCTP_SCOPE_LINK, gfp,
  						   flags);
  			if (error < 0)
  				goto out;
  		}
  	}
  
  out:
  	if (error)
  		sctp_bind_addr_clean(dest);
  
  	return error;
  }

  /* Exactly duplicate the address lists.  This is necessary when doing
   * peer-offs and accepts.  We don't want to put all the current system
   * addresses into the endpoint.  That's useless.  But we do want duplicat
   * the list of bound addresses that the older endpoint used.
   */
  int sctp_bind_addr_dup(struct sctp_bind_addr *dest,
  			const struct sctp_bind_addr *src,
  			gfp_t gfp)
  {
  	struct sctp_sockaddr_entry *addr;

  	int error = 0;
  
  	/* All addresses share the same port.  */
  	dest->port = src->port;

  	list_for_each_entry(addr, &src->address_list, list) {

  		error = sctp_add_bind_addr(dest, &addr->a, sizeof(addr->a),
  					   1, gfp);

  		if (error < 0)
  			break;
  	}
  
  	return error;
  }

  /* Initialize the SCTP_bind_addr structure for either an endpoint or
   * an association.
   */
  void sctp_bind_addr_init(struct sctp_bind_addr *bp, __u16 port)
  {

  	INIT_LIST_HEAD(&bp->address_list);
  	bp->port = port;
  }
  
  /* Dispose of the address list. */
  static void sctp_bind_addr_clean(struct sctp_bind_addr *bp)
  {

  	struct sctp_sockaddr_entry *addr, *temp;

  
  	/* Empty the bind address list. */

  	list_for_each_entry_safe(addr, temp, &bp->address_list, list) {
  		list_del_rcu(&addr->list);

  		kfree_rcu(addr, rcu);

  		SCTP_DBG_OBJCNT_DEC(addr);
  	}
  }
  
  /* Dispose of an SCTP_bind_addr structure  */
  void sctp_bind_addr_free(struct sctp_bind_addr *bp)
  {
  	/* Empty the bind address list. */
  	sctp_bind_addr_clean(bp);

  }
  
  /* Add an address to the bind address list in the SCTP_bind_addr structure. */
  int sctp_add_bind_addr(struct sctp_bind_addr *bp, union sctp_addr *new,

  		       int new_size, __u8 addr_state, gfp_t gfp)

  {
  	struct sctp_sockaddr_entry *addr;
  
  	/* Add the address to the bind address list.  */

  	addr = kzalloc(sizeof(*addr), gfp);

  	if (!addr)
  		return -ENOMEM;

  	memcpy(&addr->a, new, min_t(size_t, sizeof(*new), new_size));

  
  	/* Fix up the port if it has not yet been set.
  	 * Both v4 and v6 have the port at the same offset.
  	 */

  	if (!addr->a.v4.sin_port)
  		addr->a.v4.sin_port = htons(bp->port);

  	addr->state = addr_state;

  	addr->valid = 1;

  	INIT_LIST_HEAD(&addr->list);

  
  	/* We always hold a socket lock when calling this function,
  	 * and that acts as a writer synchronizing lock.
  	 */
  	list_add_tail_rcu(&addr->list, &bp->address_list);

  	SCTP_DBG_OBJCNT_INC(addr);
  
  	return 0;
  }
  
  /* Delete an address from the bind address list in the SCTP_bind_addr
   * structure.
   */

  int sctp_del_bind_addr(struct sctp_bind_addr *bp, union sctp_addr *del_addr)

  {

  	struct sctp_sockaddr_entry *addr, *temp;

  	int found = 0;

  	/* We hold the socket lock when calling this function,
  	 * and that acts as a writer synchronizing lock.
  	 */
  	list_for_each_entry_safe(addr, temp, &bp->address_list, list) {

  		if (sctp_cmp_addr_exact(&addr->a, del_addr)) {

  			/* Found the exact match. */

  			found = 1;

  			addr->valid = 0;
  			list_del_rcu(&addr->list);
  			break;

  		}
  	}

  	if (found) {

  		kfree_rcu(addr, rcu);

  		SCTP_DBG_OBJCNT_DEC(addr);

  		return 0;

  	}

  	return -EINVAL;
  }
  
  /* Create a network byte-order representation of all the addresses
   * formated as SCTP parameters.
   *
   * The second argument is the return value for the length.
   */
  union sctp_params sctp_bind_addrs_to_raw(const struct sctp_bind_addr *bp,

  					 int *addrs_len,

  					 gfp_t gfp)

  {
  	union sctp_params addrparms;
  	union sctp_params retval;
  	int addrparms_len;
  	union sctp_addr_param rawaddr;
  	int len;
  	struct sctp_sockaddr_entry *addr;
  	struct list_head *pos;
  	struct sctp_af *af;
  
  	addrparms_len = 0;
  	len = 0;
  
  	/* Allocate enough memory at once. */
  	list_for_each(pos, &bp->address_list) {
  		len += sizeof(union sctp_addr_param);
  	}
  
  	/* Don't even bother embedding an address if there
  	 * is only one.
  	 */
  	if (len == sizeof(union sctp_addr_param)) {
  		retval.v = NULL;
  		goto end_raw;
  	}
  
  	retval.v = kmalloc(len, gfp);
  	if (!retval.v)
  		goto end_raw;
  
  	addrparms = retval;

  	list_for_each_entry(addr, &bp->address_list, list) {

  		af = sctp_get_af_specific(addr->a.v4.sin_family);
  		len = af->to_addr_param(&addr->a, &rawaddr);

  		memcpy(addrparms.v, &rawaddr, len);
  		addrparms.v += len;
  		addrparms_len += len;
  	}
  
  end_raw:
  	*addrs_len = addrparms_len;
  	return retval;
  }
  
  /*
   * Create an address list out of the raw address list format (IPv4 and IPv6
   * address parameters).
   */
  int sctp_raw_to_bind_addrs(struct sctp_bind_addr *bp, __u8 *raw_addr_list,

  			   int addrs_len, __u16 port, gfp_t gfp)

  {
  	union sctp_addr_param *rawaddr;
  	struct sctp_paramhdr *param;
  	union sctp_addr addr;
  	int retval = 0;
  	int len;
  	struct sctp_af *af;
  
  	/* Convert the raw address to standard address format */
  	while (addrs_len) {
  		param = (struct sctp_paramhdr *)raw_addr_list;
  		rawaddr = (union sctp_addr_param *)raw_addr_list;
  
  		af = sctp_get_af_specific(param_type2af(param->type));
  		if (unlikely(!af)) {
  			retval = -EINVAL;
  			sctp_bind_addr_clean(bp);
  			break;
  		}

  		af->from_addr_param(&addr, rawaddr, htons(port), 0);

  		if (sctp_bind_addr_state(bp, &addr) != -1)
  			goto next;

  		retval = sctp_add_bind_addr(bp, &addr, sizeof(addr),
  					    SCTP_ADDR_SRC, gfp);

  		if (retval) {
  			/* Can't finish building the list, clean up. */
  			sctp_bind_addr_clean(bp);
  			break;
  		}

  next:

  		len = ntohs(param->length);
  		addrs_len -= len;
  		raw_addr_list += len;
  	}
  
  	return retval;
  }
  
  /********************************************************************
   * 2nd Level Abstractions
   ********************************************************************/
  
  /* Does this contain a specified address?  Allow wildcarding. */

  int sctp_bind_addr_match(struct sctp_bind_addr *bp,

  			 const union sctp_addr *addr,
  			 struct sctp_sock *opt)
  {
  	struct sctp_sockaddr_entry *laddr;

  	int match = 0;
  
  	rcu_read_lock();
  	list_for_each_entry_rcu(laddr, &bp->address_list, list) {
  		if (!laddr->valid)
  			continue;
  		if (opt->pf->cmp_addr(&laddr->a, addr, opt)) {
  			match = 1;
  			break;
  		}

  	}

  	rcu_read_unlock();

  	return match;

  }

  int sctp_bind_addrs_check(struct sctp_sock *sp,
  			  struct sctp_sock *sp2, int cnt2)
  {
  	struct sctp_bind_addr *bp2 = &sp2->ep->base.bind_addr;
  	struct sctp_bind_addr *bp = &sp->ep->base.bind_addr;
  	struct sctp_sockaddr_entry *laddr, *laddr2;
  	bool exist = false;
  	int cnt = 0;
  
  	rcu_read_lock();
  	list_for_each_entry_rcu(laddr, &bp->address_list, list) {
  		list_for_each_entry_rcu(laddr2, &bp2->address_list, list) {
  			if (sp->pf->af->cmp_addr(&laddr->a, &laddr2->a) &&
  			    laddr->valid && laddr2->valid) {
  				exist = true;
  				goto next;
  			}
  		}
  		cnt = 0;
  		break;
  next:
  		cnt++;
  	}
  	rcu_read_unlock();
  
  	return (cnt == cnt2) ? 0 : (exist ? -EEXIST : 1);
  }

  /* Does the address 'addr' conflict with any addresses in
   * the bp.
   */
  int sctp_bind_addr_conflict(struct sctp_bind_addr *bp,
  			    const union sctp_addr *addr,
  			    struct sctp_sock *bp_sp,
  			    struct sctp_sock *addr_sp)
  {
  	struct sctp_sockaddr_entry *laddr;
  	int conflict = 0;
  	struct sctp_sock *sp;
  
  	/* Pick the IPv6 socket as the basis of comparison
  	 * since it's usually a superset of the IPv4.
  	 * If there is no IPv6 socket, then default to bind_addr.
  	 */
  	if (sctp_opt2sk(bp_sp)->sk_family == AF_INET6)
  		sp = bp_sp;
  	else if (sctp_opt2sk(addr_sp)->sk_family == AF_INET6)
  		sp = addr_sp;
  	else
  		sp = bp_sp;
  
  	rcu_read_lock();
  	list_for_each_entry_rcu(laddr, &bp->address_list, list) {
  		if (!laddr->valid)
  			continue;
  
  		conflict = sp->pf->cmp_addr(&laddr->a, addr, sp);
  		if (conflict)
  			break;
  	}
  	rcu_read_unlock();
  
  	return conflict;
  }

  /* Get the state of the entry in the bind_addr_list */
  int sctp_bind_addr_state(const struct sctp_bind_addr *bp,
  			 const union sctp_addr *addr)
  {
  	struct sctp_sockaddr_entry *laddr;
  	struct sctp_af *af;

  
  	af = sctp_get_af_specific(addr->sa.sa_family);
  	if (unlikely(!af))

  		return -1;

  	list_for_each_entry_rcu(laddr, &bp->address_list, list) {
  		if (!laddr->valid)
  			continue;

  		if (af->cmp_addr(&laddr->a, addr))
  			return laddr->state;

  	}

  	return -1;

  }

  /* Find the first address in the bind address list that is not present in
   * the addrs packed array.
   */
  union sctp_addr *sctp_find_unmatch_addr(struct sctp_bind_addr	*bp,
  					const union sctp_addr	*addrs,
  					int			addrcnt,
  					struct sctp_sock	*opt)
  {
  	struct sctp_sockaddr_entry	*laddr;
  	union sctp_addr			*addr;
  	void 				*addr_buf;
  	struct sctp_af			*af;

  	int				i;

  	/* This is only called sctp_send_asconf_del_ip() and we hold
  	 * the socket lock in that code patch, so that address list
  	 * can't change.
  	 */
  	list_for_each_entry(laddr, &bp->address_list, list) {

  		addr_buf = (union sctp_addr *)addrs;
  		for (i = 0; i < addrcnt; i++) {

  			addr = addr_buf;

  			af = sctp_get_af_specific(addr->v4.sin_family);

  			if (!af)

  				break;

  			if (opt->pf->cmp_addr(&laddr->a, addr, opt))

  				break;
  
  			addr_buf += af->sockaddr_len;
  		}
  		if (i == addrcnt)

  			return &laddr->a;

  	}
  
  	return NULL;
  }
  
  /* Copy out addresses from the global local address list. */

  static int sctp_copy_one_addr(struct net *net, struct sctp_bind_addr *dest,

  			      union sctp_addr *addr, enum sctp_scope scope,
  			      gfp_t gfp, int flags)

  {
  	int error = 0;

  	if (sctp_is_any(NULL, addr)) {

  		error = sctp_copy_local_addr_list(net, dest, scope, gfp, flags);

  	} else if (sctp_in_scope(net, addr, scope)) {

  		/* Now that the address is in scope, check to see if
  		 * the address type is supported by local sock as
  		 * well as the remote peer.
  		 */
  		if ((((AF_INET == addr->sa.sa_family) &&

  		      (flags & SCTP_ADDR4_ALLOWED) &&

  		      (flags & SCTP_ADDR4_PEERSUPP))) ||
  		    (((AF_INET6 == addr->sa.sa_family) &&
  		      (flags & SCTP_ADDR6_ALLOWED) &&
  		      (flags & SCTP_ADDR6_PEERSUPP))))

  			error = sctp_add_bind_addr(dest, addr, sizeof(*addr),
  						   SCTP_ADDR_SRC, gfp);

  	}
  
  	return error;
  }
  
  /* Is this a wildcard address?  */

  int sctp_is_any(struct sock *sk, const union sctp_addr *addr)

  {

  	unsigned short fam = 0;
  	struct sctp_af *af;
  
  	/* Try to get the right address family */
  	if (addr->sa.sa_family != AF_UNSPEC)
  		fam = addr->sa.sa_family;
  	else if (sk)
  		fam = sk->sk_family;
  
  	af = sctp_get_af_specific(fam);

  	if (!af)
  		return 0;

  	return af->is_any(addr);
  }
  
  /* Is 'addr' valid for 'scope'?  */

  int sctp_in_scope(struct net *net, const union sctp_addr *addr,
  		  enum sctp_scope scope)

  {

  	enum sctp_scope addr_scope = sctp_scope(addr);

  
  	/* The unusable SCTP addresses will not be considered with
  	 * any defined scopes.
  	 */
  	if (SCTP_SCOPE_UNUSABLE == addr_scope)
  		return 0;
  	/*
  	 * For INIT and INIT-ACK address list, let L be the level of
  	 * of requested destination address, sender and receiver
  	 * SHOULD include all of its addresses with level greater
  	 * than or equal to L.

  	 *
  	 * Address scoping can be selectively controlled via sysctl
  	 * option

  	 */

  	switch (net->sctp.scope_policy) {

  	case SCTP_SCOPE_POLICY_DISABLE:

  		return 1;

  	case SCTP_SCOPE_POLICY_ENABLE:
  		if (addr_scope <= scope)
  			return 1;
  		break;
  	case SCTP_SCOPE_POLICY_PRIVATE:
  		if (addr_scope <= scope || SCTP_SCOPE_PRIVATE == addr_scope)
  			return 1;
  		break;
  	case SCTP_SCOPE_POLICY_LINK:
  		if (addr_scope <= scope || SCTP_SCOPE_LINK == addr_scope)
  			return 1;
  		break;
  	default:
  		break;
  	}

  
  	return 0;
  }

  int sctp_is_ep_boundall(struct sock *sk)
  {
  	struct sctp_bind_addr *bp;
  	struct sctp_sockaddr_entry *addr;
  
  	bp = &sctp_sk(sk)->ep->base.bind_addr;
  	if (sctp_list_single_entry(&bp->address_list)) {
  		addr = list_entry(bp->address_list.next,
  				  struct sctp_sockaddr_entry, list);
  		if (sctp_is_any(sk, &addr->a))
  			return 1;
  	}
  	return 0;
  }

  /********************************************************************
   * 3rd Level Abstractions
   ********************************************************************/
  
  /* What is the scope of 'addr'?  */

  enum sctp_scope sctp_scope(const union sctp_addr *addr)

  {
  	struct sctp_af *af;
  
  	af = sctp_get_af_specific(addr->sa.sa_family);
  	if (!af)
  		return SCTP_SCOPE_UNUSABLE;
  
  	return af->scope((union sctp_addr *)addr);
  }